Glass 1983.

Methods	Stratified random allocation; double‐blind (A); placebo‐controlled; 16% drop out after 2.5 years (study duration = 2.5 years). Natural losses; no losses due to any adverse effects; any differential group losses not assessable.
Participants	853 children analysed at 2.5 years (available at final examination). Age range at start: 7‐11 years (average = 9). Surfaces affected at start: 2.1 DFS. Background exposure to fluoride: water. Year study began: 1976. Location: USA.
Interventions	FT (2 groups) versus PL (both SMFP groups = 1000 ppm F). School use/supervised, daily (appropriate toothpastes and toothbrushes also provided for home use). Abrasive system: IMP (main abrasive) in one SMFP and placebo toothpaste, Ca carbonate in the other SMFP toothpaste.
Outcomes	2.5yNetDFS increment ‐ (CA)cl+(ER)xr. Reported at 2.5 years follow up. DFT. CIR.
Notes	Participants randomised (N = 1017); numbers by group NR. Baseline characteristics (age, DFS, DFT, SAR, TAR) 'balanced' (for DFT/DFS). Clinical (VT) caries assessment by two examiners (independently); diagnostic threshold = CA; state of tooth eruption included = E/U. Radiographic assessment (2 postBW) by two examiners (independently); diagnostic threshold = ER. Results of one examiner chosen (findings consistent throughout).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear